Hopefully
2026年7月6日(月) 21:14 Christos Margiolis <[email protected]>:
> On Mon Jul 6, 2026 at 12:15 AM EEST, Kevin Bowling wrote:
> > Hi,
> >
> > I am working on a more complete pipewire audio sink
> > (audio/pipewire-spa-oss-ng) and ran into an interesting case where a
> > user has an interface with 10 channels on one dsp device.
> >
> > In sys/dev/sound/pcm/channel.h we currently have:
> > #define CHN_2NDBUFMAXSIZE 131072
> >
> > This is workable but results in a tighter bound than my sink requests.
> >
> > I am wondering if we should dynamically scale, something like this:
> >
> > #define CHN_2NDBUFMAXSIZE_DEFAULT 131072
> > #define CHN_2NDBUFMAXSIZE_LIMIT 1048576
> >
> > static uint32_t
> > chn_2ndbuf_maxsize(struct pcm_channel *c)
> > {
> > struct snd_dbuf *bs = c->bufsoft;
> > uint64_t bytes;
> >
> > /* e.g. allow up to about 100 ms of the actual stream. */
> > bytes = (uint64_t)bs->align * bs->spd / 10;
> >
> > if (bytes < CHN_2NDBUFMAXSIZE_DEFAULT)
> > bytes = CHN_2NDBUFMAXSIZE_DEFAULT;
> > if (bytes > chn_2ndbuf_maxsize_limit)
> > bytes = chn_2ndbuf_maxsize_limit;
> >
> > return (uint32_t)bytes;
> > }
> >
> > I can send a complete patch for review if it seems like a reasonable
> direction.
> >
> > Regards,
> > Kevin Bowling
>
> Feel free to propose the patch and add me as a reviewer, I was actually
> meaning to either remove this or refactor this. Thank you!
>
> Christos
>
>
